One in five U.S. adults still used tobacco in 2015, and most were smokers, a new federal government study of tobacco products reported Thursday.

There were 49 million tobacco users, according to the 2015 U.S. National Health Interview Survey. Of those, 42 million used either cigarettes, cigars or hookahs and water pipes.

The remainder used electronic cigarettes or smokeless tobacco products such as chewing tobacco, snuff, dip, snus, and dissolvable tobacco.

Tobacco use was more common among men than among women, and more common among younger adults, aged 25 to 44, than older adults, aged 65 and older.

Tobacco use was also higher among certain people: those in the Midwest; those with annual household incomes under $35,000; those uninsured or on Medicaid; those with a disability; and those who are lesbian, gay, or bisexual.

Tobacco use was also much higher among adults with serious psychological distress, according to the report from the U.S. Centers for Disease Control and Prevention and the U.S. Food and Drug Administration's Center for Tobacco Products.

The data also showed that 9.5 million American adults reported "every day" or "some day" use of at least two tobacco products, with cigarettes the most commonly used product (15 percent) followed by e-cigarettes (3.5 percent).

"Too many Americans are harmed by cigarette smoking, which is the nation's leading preventable cause of death and disease," CDC Director Dr. Brenda Fitzgerald said in an agency news release.

Smoking kills about 480,000 Americans each year and about 16 million Americans have a smoking-related illness.

According to FDA Commissioner Dr. Scott Gottlieb, "These results make clear that more action is needed to reduce the disease and death caused by cigarette use -- and the FDA has announced a comprehensive approach to do just that."

Gottlieb said, "As part of this effort, the FDA is focusing on the role that nicotine plays in creating and sustaining addiction to combustible cigarettes, by seeking to regulate the nicotine content in cigarettes to render them minimally or non-addictive. This will be coupled with efforts to encourage innovation of potentially less harmful products, including electronic nicotine delivery systems."

The findings were published in the Nov. 9 issue of the CDC's Morbidity and Mortality Weekly Report.